Direct preparation of pyrrolo[3,4-C]pyrroles

Abstract

A process is disclosed for the direct preparation of pigmentary 1,4-diketopyrrolo-[3,4-c]pyrroles of the formula (I) wherein each of R 1 and R 2 independently of the other is an isocyclic or heterocyclic aromatic radical, which process comprises heating an appropriate molar ratio of a disuccinate with a nitrile of the formula (II) R 1 —CN  (II) or of the formula (III) R 2 —CN  (III) or with mixtures of said nitrites, in an organic solvent and in the presence of a strong base and an effective amount of a selected particle growth inhibitor of formula (IV)-(X), and then obtaining the compound of formula (I) from the reaction product by protolysis. The process yields pigmentary 1,4-diketopyrrolo-[3,4-c]pyrroles directly, i.e., without the need for additional particle-size reducing aftertreatments. Also disclosed is a composition comprising a pigmentary 1,4-diketopyrrolo-[3,4-c]pyrrole and the particle growth inhibitor. These pigment compositions are useful for pigmenting high molecular weight organic materials.

What is claimed is:  
     
       1. A pigment composition comprising 
       a) a 1,4-diketopyrrolo[3,4-c]pyrrole of the formula (I)                    
       wherein each of R 1  and R 2  independently of the other is an isocyclic or heterocyclic aromatic radical; and  
       b) an effective crystal growth inhibiting amount of a compound of formula (IV)                    
       wherein R 3 , R 4  and R 5  are, each independently of the other, hydrogen, chlorine, bromine, fluorine, C 1 -C 6 alkyl, C 1 -C 6 alkoxy or an isocyclic or heterocyclic aromatic radical and Q is a quinacridone or diketopyrrolopyrrole moiety;  
       a compound of formula (V)                    
       wherein R 6 , R 7  and R 8  are, each independently of the other, hydrogen, chlorine, bromine, fluorine, C 1 -C 6 alkyl, C 1 -C 6 alkoxy or an isocyclic or heterocyclic aromatic radical and Q is as defined above;  
       a compound of formula (VI)                    
       wherein R 9 , R 10 , R 11  and R 12  are, each independently of the other, hydrogen, chlorine, bromine, fluorine, C 1 -C 6 alkyl, C 1 -C 6 alkoxy or an isocyclic or heterocyclic aromatic radical and Q is as defined above;  
       a compound of formula (VII)  
       
         
           Q—SO 3 X  (VII)  
         
       
       wherein X is hydrogen, sodium, potassium, magnesium, calcium, strontium or aluminum and Q is as defined above;  
       a compound of formula (VIII)                    
       wherein n is an integer from 2 to 4; R 13  and R 14  are, each independently of the other, C 1 -C 6 alkyl or together with the nitrogen atom to which they are bonded form a 5- or 6-membered heterocyclic ring; and Q is as defined above;  
       a compound of formula (IX)                    
       wherein R 15  is hydrogen, chlorine, bromine, fluorine, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, phenyl, di-C 1 -C 6 alkylamino, C 1 -C 6 alkylthio, phenylthio or phenoxy, and Q is as defined a compound is substituted by from 0 to 6 moles of —SO3M per mole of said compound, wherein M is hydrogen or a metal or ammonium cation;  
       or a compound of the formula (X)                    
       wherein R 27  and R 28  are, each independently of the other, hydrogen, chlorine, bromine, fluorine, C 1 -C 6 alkyl, C 1 -C 6 alkoxy or an isocyclic or heterocyclic aromatic radical and Q is as defined above,  
       wherein the pigment composition is polymorphically pure as compared to the pigment without growth inhibitor.  
     
     
       2. A high molecular weight organic material pigmented with the pigment composition of  claim 1 .